Memory Systems Flashcards
What is Computer Memory
Memory is a temporary data storage unit or data storage device where data and programs to be operated on by the processors must reside, where data is to be processed and instructions required for processing are stored
How Does Computer Memory work?
When you open a program, it is loaded from the secondary memory to the primary memory. Because the primary memory is accessed more quickly, the open-source software can connect to the computer’s processor more quickly. The primary memory is readily accessible from temporary memory slots and other storage sites. Memory is volatile, which means that data is kept temporarily in memory. Data saved in volatile memory is automatically destroyed when a computing device is turned off.
Mention Types of Memory
- Primary memory
- Secondary memory
- Cache memory
What is primary memory
Primary memory is also known as the main memory of the computer system. It is used to store data and programs or instructions during computer operations. It uses Semi-conductor technology and hence is commonly called Semi-conductor memory
Types of Primary memory
-Random Access Memory (RAM)
- Read Only Memory (ROM)
Discuss RAM
RAM is a volatile memory and as such can only store information based on the power supply. If the power supply fails/stopped, all the data and information on the memory will be lost. RAM is used for booting up and starting the computer. It temporarily stores programs/data which has to be executed by the processor.
Types of RAM
- Static RAM (SRAM)
- Dynamic RAM (DRAM)
Discuss ROM
ROM is a non-volatile memory and as such can store information even when there is a power supply failure. ROM is used to store information that is used to operate the system. As it’s name implies, we can only read the programs and data that is stored on it. It contains some electronic fuses that can be programmed for a piece of specific information. The information is stored in the ROM is in binary format. It is also known as permanent memory.
Types of ROM
- Masked ROM (MROM)
- Programmable ROM (PROM)
- Erasable PROM (EPROM)
Discuss Secondary memory
Secondary memory is also known as auxiliary memory and backup memory. It is a non-volatile memory and to used store large amount of data or information. The data or information stored in secondary memory is permanent, and it is slower than primary memory. A CPU cannot access secondary memory directly. The data/information from the auxiliary memory is first transferred to the main memory, and then the CPU can access it.
Characteristics of Secondary memory
- It’s a slow memory but reusable
- It’s a reliable and non-volatile memory
- It’s cheaper than primary memory
- The storage capacity of secondary memory is large
- A computer system can run without secondary memory
- In secondary memory, data is stored permanently even when the power is off
Types Of Secondary memory
- Magnetic Tapes
- Magnetic Disk
- Optical Disks
Types of Optical Disks
- CD-ROM
- WRITE ONCE READ MANY (WORM)
- DVD (Digital Versatile/Video Disk)
Discuss Cache memory
Cache memory is a type of high-speed Semi-conductor memory that can help the CPU run faster. Between the CPU and the main memory, it serves as a buffer. It is used to store the data and programs that the CPU uses the most frequently.
Advantages of Cache memory
- It is faster than the main memory
- When compared to the main memory, it takes less time to access it.
- It keeps the programs that can be run in a short amount of time
- It stores data in temporary use
Disadvantage of Cache memory
- Because of the Semi-conductor used, it is very expensive
- The size of the Cache (amount of data it can store) is usually small
Discuss Memory Unit
A memory unit is a collection of storage cells together with associate circuits needed to transfer information in and out of the storage. A memory word is a group of IS and OS and many represent a number, an instruction code, one or more alphanumeric characters or any other binary coded information. A group of 8 bits is called a byte. Most computer memory, the words whose number of bits is a multiple of 8, 16 bit words contains two bytes, and 32 bit words is made up of 4 bytes. The capacity of memories in commercial computers are usually stated as the total number of bytes that can be stored. The internal structure of a memory unit is specified by the number of words it contains and the number of bits in each word. Each word in memory is assigned an identification number, called an address starting from 0 and continuing too 1,2,3 and up to 2^(k-1), where k is the number of address lines i.e, the process of locating words in memory is the same and requires an equal amount of time no matter where the cells located physically in memory.
Discuss physical and logical memory, differentiate between them
Physical memory is the actual hardware of a computer system that stores data. Logical memory is also known as virtual memory and is an abstraction provided by the OS for programs to use more memory than is physically available.
Discuss physical and logical memory, differentiate between them
Physical memory is the actual hardware of a computer system that stores data. Logical memory is also known as virtual memory and is an abstraction provided by the OS for programs to use more memory than is physically available.
